HISTORIC NOTE

The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.

Copyright 2005, Board of Trustees, University
of Florida

0O
- c,~_c~dl-\

I~

NINTH ANNUAL RICE FIELD DAY

UNIVERSITY OF FLORIDA
EVERGLADES RESEARCH AND EDUCATION CENTER
INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES
COOPERATIVE EXTENSION SERVICE
BELLE GLADE, FLORIDA
AUGUST 1,1986

Belle Glade EREC Research Report EV-1986-6

Discussion Session

NINTH ANNUAL RICE FIELD DAY

EVERGLADES RESEARCH AND EDUCATION CENTER
BELLE GLADE, FLORIDA

AUGUST 1, 1986

DR. DAVID B. JONES, PRESIDING
ASSISTANT PROFESSOR, RICE AGRONOMY

Page

8:30 AM Welcome Remarks/Opening Comments

8:35 AM The Purpose and Activities of
the Florida Rice Council

8:40 AM Using IFAS Rice Budget Generator

9:05 AM Distribution of Rice Stink Bugs
in Florida Rice Fields

9:20 AM Weed Management Systems in
Everglades Rice Culture

9:35 AM Correcting Seedling Micro-
nutrient Problems in the
Everglades

9:50 AM The Use of Calcium Silicate
Slag in a Rice-Sugarcane
Rotation on Everglades
Histosols

V. H. Waddill,
Center Director

R. Roth, President
Florida Rice Council

J. Alvarez ----------

R. E. Foster and -------- 11
R. H. Cherry

J. A. Dusky ----- -------- 13

G. H. Snyder ---------- 24

D. L. Anderson -------- 29

10:05 AM BREAK

10:15 AM Effect of Flooding on Bio-
chemical Properties of
Organic Soils Used for Rice
Cultivation

10:30 AM Physiological Traits Associated
with Grain Yield of Rice Grown
on South Florida Histosol

K. R. Reddy ----------44

F. B. Laroche ----------- 50

COVER University of Florida researchers, Drs. F. P. Gardener of Gainesville and
D, B. Jones of Everglades REC, assist-graduate student F. B. Laroche in
taking light measurements in his study investigating rice plant growth and
development in the Everglades. Mr. Laroche's studies were made possible
through a part time assistantship provided by the Florida Rice Council.

Discussion Session

Page

10:45 AM Ratoon Crop Management D. B. Jones ------------- 61

11:00 AM The Collection of Life History K. Fucik ----------------- 70
Data for.the Crawfish Procambarus
Fallax and P. Alleni, in regard
to Their Aquaculture Potential

11:30 AM Tour Everglades REC Rice Research and
Demonstration Plots

12:15 PM LUNCH Dutch Treat

1:15 PM Field Tour Visits to commercial
rice fields and a local rice mill

USING IFAS RICE BUDGET GENERATOR

Jose Alvarez

An enterprise budget is a systematic listing of income, expenses,
capital, labor, and machinery requirements for a given crop.
Microcomputers are useful tools in this area because they perform the
calculations in a faster and more accurate manner than when they are
developed by hand.

The "Rice Budget Generator" distributed by IFAS analyzes first the
plant crop, then the ratoon crop and, finally, the two operations
combined. The numbers in the example run presented in the following 13
Tables (where the numbers within boxes are input figures provided by the
users while the rest are calculated by the program) pertain to a
500-acre rice operation that complements sugarcane production in south
Florida. The budget, however, can be used for smaller or larger
operations, by entering the appropriate data, and is also relevant to
rice producers in other areas.

The program consists of a user's manual (which contains all the
operating instructions) and a distribution disk that must be used in
conjuction with Lotus 1-2-3. An IBM Personal Computer, or compatible,
with a minimum of 192 K of RAM is required. Version 1, 1A or 2 of Lotus
1-2-3 is also necessary. All versions require at least two disk drives
and versions 1 and 2 support a hard disk. If printed reports are
desired, a printer is also needed.

For more information, on this or other programs available, call
(904) 392-7853 or write to:

IFAS Software Communication and Distribution
G022 McCarty Hall
University of Florida
Gainesville, Fl 32611

Jose Alvarez is Area Economist, Food and Resource Economics Department,
University of Florida, Everglades Research and Education Center, Belle
Glade, Fl 33430.

Table 1.-Screen access menu.

RICE BUDGET GENERATOR

Screen Access Menu
SECTION #
-----------~--------------
-----I----~--~-I----------
GENERAL INFORMATION 1
MACHINE AND EQUIPMENT
MACHINERY USE AND OPERATIONS 3
PRE-HARVEST COSTS 4
TOTAL COSTS (with varying yields)
a) Expected 5
b) Lower 6
c) Higher 7
RETURNS TO FACTORS OF PRODUCTION a
SENSITIVITY ANALYSIS 9
PARTIAL BUDGET FOR RATOON CROP 10
TOTAL RETURNS TO FACTORS OF PRODUCTION 11
HELP MENU 12
Enter the number corresponding to the section you want to reach:
Enter the number corresponding to the section you want to reachs====^si

Table 2.-General information section.

General information:
Farm name:

Number of acres
Exptd. Dry Yield (cwt/f
Expected Price ($/cwt)
Int.rate Oper. loans (
Int.rate Mach. loans (
Operator's wage ($/hr)
Labor use (hrs/day)
Machinery use (hrs/day
Fuel cost ($/gallon)

Haul. dryer ($/cwt/mili
Distance to dryer(mile
Moisture at harvest (%
Moisture desired (%)
Drying cost (P/cwt)

Everades 'Rice, Inc.

500
A) 40
10
%) 13.00%
%) 13.00%
5.50
10
) 9
1.00

e) 0.05
s) 10
) 21.o00
12.50%
1. 40

able 3.-Machinery and equipment section.

MACHINERY AND EQUIPMENT

ITEM
Tractor 1, 185 HP
Tractor 2, 140 HP
Tractor 3, 120 HP
Disk offset, 9'
Disk offset, 11'
Disk harrow, 21'
Laser plane
Roller, 10'
Grain drill, 10'
Hopper trailer
SP combine, 16'
Bulldozer
Levee disc

New Cost

60, 000
45,000
35, 000
4,000
5,000
9,000
30,000
1,530
2,880
7,200
73,500
39,600
10,000

Fuel Annual
gal/hr. Use (Hrs)

8.0 2000
4.5 1500
3.8 1500
500
500
500
1500
.150
150
300
4.5 300
5.1 600
40

--Fixed cost--

Annual

12,090
9,068
7,053
806
1,008
1,814
6,045
308
580
1,451
14,810
7,979
2,015

$/A

13.03-
4.76
3.48
0.73
1.04
1.09
7.25
0.69
1.16
2.90
29.62
0.75
2.83

Variable
Cost/Hr

S9.00
5.50
4.80
0. 00
0. 00
0.00
0.00
0.00
0.00
0. 00
5.50
6.10
0.00

TOTAL 322,710 65,026 69.33

Table 4.- Machinery use and operations.

MACHINERY USE

Land Land
Breaking Disking

Land Land
Level Disking

Plant- Roll-
ing ing

Times Over

Tractor 1, 185 HP
Tractor 2, 140 HP
Tractor 3, 120 HP
Disk offset, 9'
Disk offset, 11'
Disk harrow, 21'
Laser plane
Roller, 10'
Grain drill, 10'
Hopper trailer
SP combine, 16'
Bulldozer
Levee disc

MACHINERY USE

Times Over

Tractor 1, 185.HP
Tractor 2, 140 HP
Tractor 3, 120 HP
Disk offset, 9'
Disk offset, 11'
Disk harrow, 21'
Laser plane
Roller, 10'
Grain drill, 10"
Hopper trailer
SP combine, 16'
Bulldozer
Levee disc

2 2 1' 2 1

------------cres/Day-------------------
0 0 5 60 0 .
40 0 0 0 0 80
0 35 0 0 40 0
40 0 0 0 0 0
0 35 0 0 0 0
0 C 0 60 0 0
0 0 5 0 0 0
0 ) 0 0 0 80
0 0 0 0 40 0
0 0 0 0 C 0
0 0 0 0 0 0
0 0 C0 0 O
0 0 0 0 0 0

Build Destruc.
Levees Levees Other
------------ ---------

I I

1 0

160 0 0

0 0 0
0 0 0
0 0 0
O O C 0
0 0 0

O 0 0
0) 0 0

O C O
0 0
0 0 0

0 160 0
160 0 0

Bli&IW%b~-~------1_~~ I

1

Raara~----^-, I---ls~- ------- --r. ------~--I

-- ----- ~---.~I __ ____~_ __~ ~

"-""'

-----------------__res/ y-_--------------

Table 5.- Pre-harvest costs.

PRE-HARVEST COSTS

I. VARIABLE COSTS
Seed
Fertilizer
Herbicide
Fungicide
Insecticide
Surveying
Aircraft
Labor
Mach. & Equip.
Irrigation
Miscel aneous
Interest

Times

Unit Quantity

0

ver -Price C
---- ----- -

Ib. 100 1 0.22
ton 0.05 1 240.00
gal. 0.5 2 9.75
Ib. 1 2 8.25
gal 0.125 2 10.56
Acre 1 0 0.00
Acre 1 5 3.00
Hours 4.217 1 5.50
Hours
Acre-inch 32 1 0.50
% 10. 00% --- I

7.-

13.00%

1

TOTAL VARIABLE COSTS == =======

*ost/Acre

22.00
12.00
9.75
16.50
2.64
0. 00
15.00
23.19
27.63
16.00
14.47
10.35

169.53

Per ent

12.98%
7.08%
5.75%
9.73%
1.56%
0.00%
8.85%
13.68%
16.30%
9.44%
8.54%
6.10%

100.00%

PRE-HARVEST COSTS

II.FIXED COSTS
Mach & Equip Frc
Land
Irrigation system
Other

Times
JNIT Quantity Over
---- -------- -----
om Machinery & Equipment
acre I,00 1I

Price

Section
0_7'. 00

TOTAL FIXED COSTS ==========================>

Cost/Acre

69.33
0.00
0.00
0.00

69.33

Percent

100.00%
0. 00%
0.00%
0.00%

100.00%

III.PRE-HARVEST TOTAL COST SUMMARY

VARIABLE COSTS
FIXED COSTS

PRE-HARVEST TOTAL COST =-------=============

169.53
69.33

238.87

70.97%
29. 03%

100.00%

- -- I

able 6.- Total cost per acre for the expected yield.

ASSUMING:
Expected Yield (Cwt./Acre)

TOTAL COST PER ACRE

40 <----

Activity

GROWING
HARVESTING
HAULING TO DRYER
DRYING

* acres

From above

Custom Hire
Custom Hire

# Hrs. Unit Quantity Cost/Unit

acre 1.000 238.87

1 Hr.
cwt.
cwt.

?d
?d

0.333
1.000
1.000

0.50
1.40

TOTAL COST ---------------------------------------- -

BREAKEVEN PRICE ==============

$8.23 <========

Cost/A

238.87
3.67
22.86
64.01

329.40

"

Table 7.- Total cost per acre for a 5 cwt lower yield.

ASSUMING:
Expected Yield

TOTAL COST PER ACRE

35 <----

(Cwt./Acre)

Activity

GROWING
HARVESTING
HAULING TO DRYER
DRYING

# acres

From above

Custom Hire
Custom Hire
Custom Hire

# Hrs. Unit Quantity Cost/Unit

acre 1.000 238.87

1 Hr.
cwt.
cwt.

0.303
1.000
1.000

0.50
1.40

Cost/A

238.87
3.33
20.00
56.01

TOTAL COST --------------------------------------------->

BREAKEVEN PRICE =============>

$9.09 <=== =====

Table 8.- Total cost per acre for a 5 cwt higher yield.

ASSUMING:
Expected Yield (Cwt./Acre)

TOTAL COST PER ACRE
Sttt45 45 <----

Activity

GROWING
HARVESTING
HAULING TO DRYER
DRYING

# acres

From above
Custom Hired
Custom Hired
Custom Hired

Hrs. Unit Quantity Cost/Unit

acre 1.000 238.87

1 Hr.
cwt.
cwt.

0.370
1.000
1. p00

Q. 50
1.40

Cost/A

238.87
4.07
25.72
72.01

TOTAL COST ------------------------------7---------------->

BREAKEVEN PRICE ===-===-= =-==>

318.21

340.67

-- --`--

?d
id

#f

$7.57 = ===

fable 9.- Returns to factors of production for the plant crop.

RETURNS TO FACTORS OF PRODUCTION FOR THE PLANT CROP

TOTAL $

200,000

Total Revenue

Variable Costs

Return to Fixed Costs

Fixed Costs (except Land charge)

Return to land, management and risk

Land Charge

Return to management and risk

$/acre

400.00

130,034 260.07

69,966

34,666

35, 300

139.93

69.33

70.60

0 0.00

35,300

70.60

$/cwt

10,00

6.50

3.50

1.73

1.77

0.00

1.77

%

100.00%

65.02%

34.98%

17.33%

17.65%

0.00%

17.65%

Table 10.- Sensitivity analysis.

SENSITIVITY ANALYSIS
Yield Price Revenue/Acre Total Costs/Acre Net Revenue/Acre
-Cwt.- -$/cwt.- ------------------Dollars-------------------------
35 8.00 280.00 318.21 -49.40
35 9.00 315.00 318.21 -14.40
35 10,00 350.00 318.21 20.60
35 11.00 385.00 318.21 55.60
35 12.00 420.00 318.21 90.60

40 8.00 320.00 329.40 -9.40
40 9.00 360.00 329.40 30.60
40 10.00 400.00 329.40 70.60
40 11.00 440. 00 329.40 110.60
40 12.00 480.00 329.40 150.60

45 8.00 360.00 340.67 19.33
45 9.00 405.00 340.67 64.33
45 10.00 450. 00 340.67 109.33
45 11.00 495.00 340.67 154.33
45 12. 00 540. 00 340.67 199.33

able 11.- Partial budget for a ratoon crop.

INCREASED COSTS

Fungicide
Insecticide
Aircraft
Labor
Irrigation
Miscellaneous
Interest
Harvesting
Hauling to dryer
Drying

PARTIAL BUDGET FOR

UNIT Quantity

RATOON RICE
Times
Over Pt

rice

Ibs 0 0 0.00
pt. 1.5 1 1.32
acre 1 1 3.00
Hrs. 1 1 5.00
acre-inch 10 1 1.00
% 10. 00% 1
t '.20 1 074

cwt.
cwt.

TOTAL
DECREASED REVENUE
None

0. 50
1 1.40

S 0.001 .00

TOTAL ADDED COSTS (A)

CONT. PARTIAL BUDGET FOR RATOON RICE

ADDITIONAL REVENUE

Additional Rice

UNIT Quantity

cwt. 20

Ti mes
Over Price

1 iO

DECREASED COST

Other
Fixed costs (Mach & Equip)

TOTAL ADDED INCOME (B)

NET DIFFERENCE (B-A)

BREAKEVEN ANALYSIS FOR THE RATOON CROP:
st a*** **t* t* L*)&***** **L******* '

A) MinimLum Yield required to cover all costs ==

B) Minimum Price required to cover all costs ===.=>

6.03 cwt/acre

$2.86 per cwt.

$/Acre

0. 00
1.98
3.00
5.00
10.00
2.00
0.71
8.00
10.85
32.00

$73.55

$73.55

$/Acre

190.00

0.00
16.26

$206.26

$132.71

---"I~

Kn~;s~aamrr^~---~-

Bs*acetatggesatB~.r3B~ttisM^.garnrrri^^na r

~_~

able 12.- Total returns to factors of production.

TOTAL RETURNS TO FACTORS OF

TOTAL $

Total Revenue 295,000

Variable Costs 166,807

Return to Fixed Costs 128,193

Fixed Costs (except Land charge) 34,666

Return to land, management and risk 93,527

Land Charge 0

Return to management and risk 93,527

PRODUCTION

$/acre $/cwt

590.00 9.83

333.61 5.56

256.39 4.27

69.33 1.16

187.05 3.12

0.00 0.00

187.05 3.12

fable 13.- Help menu.

A

B

C ----->

H

P

R

S

HELP MENU
Returns the user to the title screen when in READY mode.

Reaches the partial budget section for the evaluation of
the ratoon crop.

Reaches the pre-harvest cost section, variable and fixed
costs sections, and the sensitivity analysis related to
total costs.

Help menu.

Prints different sections of the worksheet.

Reaches the returns to factors of production section.

Reaches the sensitivity analysis section, which shows a
series of outcomes given different yields and prices.

Reaches the Screen Access Menu when in READY mode.

100.00%

56.54%

43.46%

11.75%

31.70%

0.00%

31.70%

_ __ ___

__ __ ~_ I __

-----

-----> >

----->

-----> :

----->

----->

----->

DISTRIBUTION OF RICE STINK BUGS IN FLORIDA RICE FIELDS

R. E. Foster, R. H. Cherry, and D. B. Jones*

A previous study by Jones and Cherry showed that the rice stink bug, Oebalus

pugnax (F.), is the most important pest of rice in south Florida. Stink bug

population densities increased rapidly at heading and were most abundant during the

grain filling period in both the plant and ratoon crops. Densities exceeded the

economic threshold in 50% of the plant crop fields and in 100% of the ratoon fields.

A study has been initiated and will be completed in 1987 to determine how rice

stink bugs are distributed in rice fields. Thirty-two samples of one hundred sweeps

each will be taken with sweep nets from each of ten fields of heading rice in each

year. The samples will be taken in a systematic pattern so that all areas of the

fields are sampled. Once the stink bugs are counted it can be determined if they are

distributed evenly across the field, randomly distributed, or if they occur in

clumps. Most insect species have clumped distributions. If stink bugs are found to

be clumped, then it can be determined if they congregate in a particular portion of a

field, such as the edges. From the information gathered in this study,

recommendations can be made as to how to best sample for stink bugs in rice.

Currently, growers sample the edges of their fields and make control decisions based

on those counts. One of the main objectives of this study is to compare the edge

samples with the overall field density to determine if edge samples are an accurate

reflection of the necessity for treatment. The study will include both plant crops

and ratoon crops so that it can be determined if the stink bug distribution is

*Assistant Professor-Entomologist, Assistant Professor-Entomologist
and Assistant Professor-Rice Agronomist, Everglades REC, respectively

similar and, therefore, if sampling should be conducted in a similar manner in both

crops.

Weed Management Systems in Everglades Rice Culture

J. A. Dusky*

Several studies have been conducted during the last three growing seasons to

evaluate the performance of propanil and other herbicides with respect to weed

control efficacy and crop tolerance. A greater degree of crop phytotoxicity than

reported in other rice growing regions has been noted with the use of propanil since

rice was reintroduced as a crop in the Everglades Agricultural Area.

Propanil is the most widely utilized herbicide for weed control in Everglades

rice production. Yet, there are certain problems associated with the use of propanil

such as, reduced stand, loss of seedling vigor, increased disease, etc. This report

is a summary report of previous studies as well as an update of current research

efforts.

Propanil and Weed Control Efficacy

Studies have shown that postemergence applications of propanil at 1.5 to 3.0 Ib

ai/A provided greater than 80% control of broadleaf weeds and grass weeds for up to 2

weeks after application. Optimum application is when weeds such as spiny amaranth

(Amaranthus spinosus), purslane (Portulaca oleracea), goosegrass (Eleusine indica),

and Panicum sp. are in the 2-4 leaf stage of growth. If weeds exceed the 2-4 leaf

stage efficacy is lost. Propanil is a contact herbicide and thus provides no

residual control. The use of a residual herbicide such as thiobencarb is recommended

for use with propanil to provide continued herbicidal activity up to 6 weeks after

treatment. Even though propanil is an excellent weed control agent severe loss of

crop vigor can result from its use.

*Associate Professor-Weeds, Everglades Research and Education Center

Rice Crop Injury

Studies have been conducted to evaluate the effect of propanil rates, the growth

stage of the rice at application, and the amount of carrier used in application on

rice vigor. The use of higher rates of water in the application of propanil reduced

crop injury to propanil (Figures 1 2). Results also indicated that there was

reduced crop injury when propanil was applied at the 2-leaf and the 6-leaf stage of

growth than at the 4-leaf stage of growth (Figures 1 2). It appears that at the

2-leaf stage of growth there is not enough surface area for the spray droplets to

contact thus, increased crop vigor. At the 6-leaf stage the plant appears to be able

to recover quickly from the initial propanil injury. However, at the 4-leaf stage,

apparently the most susceptible growth stage, propanil severely reduced seedling

vigor. Crop vigor decreased as the rate of propanil was increased.

This initial reduction in seedling vigor was loss also reflected in lower yields

(Figure 3). In this study propanil was applied at two rates, 1.5 and 3.0 lb ai/A,

and at 3 growth stages. The sprayer was operated to deliver 30 gpa. Reduction in

yields due to propanil treatment was 4-leaf > 6-leaf > 2-leaf. The 3.0 Ib ai/A rate

of propanil was more detrimental to seedling vigor consequently, yields than the 1.5

lb ai/A rate of propanil.

Studies have also been conducted in growers fields to determine the affect of

rate of propanil and the amount of carrier used in application of propanil (Figure

4). The field in which this study was conducted was relatively weed-free. The yield

date indicated that as the amount of water used in application increased yields

increased. It also appears that this field even though it appeared to be relatively

weed-free had weeds which competed with the rice. As the rate of propanil was

increased yields also tended to increase.

Other observations were made during these studies with respect to time of

maturity and disease incidence. Delayed maturity and increased disease incidence of

Helminthosporum oryzae were observed when rice injury was severest, that.is, when

propanil rate was highest and the amount of carrier used in application was lowest.

Three studies were initiated in 1986 to determine the effects of propanil rate

on rice yield. Propanil was applied to all plots when the rice was in the 3 4 leaf

stage of growth. The sprayer was operated to deliver 18 gpa. Rates of propanil

utilized were 0, 1.5, 3.0, 6.0, and 12.0 lb ai/A. Phytotoxicity data was recorded 7

days after treatment. Days to hCriin- (50X), maturity date, number of panicles per

meter squared, number of grains per panicle, grain weight, and total yield will be

recorded at the time of harvest. The phytotoxicity data is presented in Table I.

Visible loss of see3lin- vigor increased as rate increased. Trial 1 was planted on

April 23, 1986 and sprayed on May 13. Trials 2 and 3 were planted on May 30, 1986

and sprayed on June 19. Rice injury was more severe in the later plantings than in

the early planting. The difference in phytotoxicity due to propanil application in

the trials may be due to differences in environmental conditions or in the source of

propanil.

From these studies and others conducted during the past several years a number

of things appear to play an important role in the use of propanil and whether or not

rice seedling vigor and subsequent yields will be affected. The rate of propanil

appears to be important. The higher the rate of propanil the more severe the damage

to the rice seedlings. From observations at the EREC during routine maintenance

operations in rice production, and studies conducted, crop vigor can be increased by

increasing the amount of water used in the application of propanil, applying propanil

very early in the day when temperatures are lower, and flushing within 24 hours after

application. It also appears that if the rice seedling is already stressed due to

lack of moistures or chlorotic due to the "iron syndrome," the injury due to propanil

will be more severe.

At the present time techniques are being examined to rapidly screen varieties

for propanil tolerance. Attempts were made to utilize chlorophyll and protein

analysis of tissue treated with varying rates of propanil but the results were

inconclusive and the techniques were time consuming. Studies are being planned to

examine the uptake, translocation, and metabolism of propanil by what appears to be a

tolerant ('Mars') and susceptible ('Lebonnet') species to determine what

physiological factors may be involved.

Control of Volunteer Rice

Studies were initiated to examine the control of volunteer rice. Emphasis was

placed on examining herbicides presently utilized in vegetable crops and those that

may be registered in the near future. Linuron (LoroxR) and prometryn

(CaparolR) were the two herbicides presently registered for use in vegetable

crops that were utilized. The other compounds were all postemergence grass

herbicides that may soon be registered.' The compounds and the rates utilized are

listed in Table 2. All the compounds were applied when the rice was in the 3 4

leaf stage. Rice seedling vigor was recorded ten days after application (Table 2).

All the postemergence grass herbicides provided excellent control of the rice,

particularly xylofop-ethyl (assure) and Select (Chevron). Rice stand counts were

made 10 and 17 days after treatment (Figure 5). When the stand counts were made if

there was more than 50% of the plant remaining green it was considered alive. The

results are expressed as percent of the control. Seventeen days after treatment less

than 20% of the rice remained living except with the sethoxydim (Poast) treatments,

the low rate of haloxyfop-methyl (Verdict), linuron and prometryn. With the

registration of the postemergence grass herbicides, the control of volunteer rice in

vegetable crops will not pose a problem.

Table 1. Effect of propanil rate on rice crop vigor seven days after
treatment. (10 = no injury, 0 = dead).

Propanil Rate
(Ib ai/A)

0
1.5
3.0
6.0
12.0

Trial 1*

9.8
9.5
8.8
7.6
6.8

Trial 2**

Trial 3**

*Average of 8 replications
**Average of 4 replications

Table 2. Effect of postemergence vwf;:t.h.lc herbicide on rice crop vigor
10 days after treatment. Average of 3 replications,
(10 no injury, 0 = dead).

Compound Rate (lb ai/A) Crop Vigor

Control ---- 9.6
*Fusilade 2000 0.125 3.5
*Fusilade 2000 0.25 2.8
*Poast 0.15 3.8
*Poast 0.30 3.0
*Verdict 0.125 4.8
*Verdict 0.25 3.0
*Bas 517 0.125 3.1
*Bas 517 0.25 2.2
**Assure 0.063 1.3
**Assure 0.125 1.1
*Select 0.075 2.8
*Select 0.1 2.0
Lorox 0.5 8.1
Caparol 2.0 8.5

*1.0% oil added to tank mix
**0.25% non-Ionic surfactant added to tank mix

Percent rice injury 2 weeks after application of 1.5 lb al/A
propanil at 3 stages of rice growth using varying amounts of
water (gal/A) in the application, 1983.

2

GRLLONS/R

Figure 1.

100

90.

80_

7 4.

60

soL

~Jb 4

Percent rice injury 2 weeks after application of 3.0 Ib ai/A
propanil at 3 stages of rice growth using varying amounts of
water (gal/A) in the application, 1983.

701-

6L

F. 1.
i-

S '

F!..

GRLLONS/R

Figure 2.

~k--.l---~ll---r--i-"a-----.

sra -----r -_-- -- --- ------ ---------------------

The effect of propanil rates and rice stage of growth at time
of application on rice yields. Sprayer was calibrated to
deliver 30 gpa.

1.5

3.0

~kII I -_

STRGE OF GROWTH

Figure 3.

60L

Figure 4. The effects of propanil rate and the amount of water used in
its application on rice yields, 1984.

3.0

1.5
C

3g0 1, I -AI I ----I

GRLLONS/R

Effect of postemergence vegetable herbicides on rice stand 10 and 17 days after treatment.
(L = low rate, H = high rate, S standard rate, FUS Fusilade, PST = Poast, VER =
Verdict, BAS = Bas 517, ASR = Assure, SEL = Select, LOR = Lorox, CAP = Caparol, See Table 2
for rates).

100.

L H L H L Hi L H L H L H S S
FUS PST VER BRS ASR SEL LOR CRP

HERBICIDE AND RRTE

Figure 5.

Correcting Rice Seedling Micronutrient Problems in the Everglades

G. H. Snyder, C. L. Elliot, and D. B. Jones*

Several studies were conducted to evaluate methods of correcting rice'

seedling chlorosis problems. Variety 'Leah' appears especially susceptable to

seedling chlorosis when grown in low-iron (Fe) soils from the eastern and

southeastern Everglades Agricultural Area. In a pot study using soil (pH 5.6) from

Shelton Farms, growth of Leah seedlings sprayed with Geigy Fe-330 at 1 kg Fe ha-1

at various time intervals following seedling emergence was compared with growth of

seedlings receiving FeSO 47H20 (FES04) at 1000 kg ha-1 at planting

and with growth of seedlings in check pots. Total plant weight 6 weeks after

emergence was greatest for rice receiving FESO4 at planting, least for the check

plants, and, for the plants receiving Fe spray, weight decreased with time interval

after emergence (Fig. 1). Total weight of plants sprayed 1-week after emergence was

statistically (P<0.05) equivalent to that of plants receiving Fe at planting. Weight

of plants sprayed 3-weeks after emergence was statistically equivalent to that of the

check pots. Repeat sprays 1, 2, and 3 weeks after emergence provided no greater

seedling weight than a single spray 1-week after emergence (data not presented). From

this study it appears that low soil Fe induced seedling chlorosis can be corrected by

post-emergence Fe sprays, but only if treatment is applied very soon after seedling

emergence.

A seedling chlorosis condition of rice also has been observed in soils

containing moderate to high amounts of Fe when the pH approaches or exceeds 7. This

*Professor-Soil Science, Chemist, and Assistant Professor-Rice Agronomy
respectively, Everglades REC

condition has been determined to be due to manganese (Mn) deficiency.

Pot and field studies were conducted to evaluate methods of correcting the Mn

deficiency. Four-week old 'Skybonnet' rice seedlings in a pot study using soil (pH

6.9) from an Okeelanta mill pond had the greatest weight when MnSO4H 20

(MNS04) was applied at 300 kg ha-1 at seeding (Table 1). Flooding shortly after

seedling emergence (12 days after planting) provided :rP.terr seedling weight than was

observed in check plot receiving no Mn or flooding, and was exceeded only by the

highest rate of MNS04 at planting (Table 1).

Plants were significantly taller than those in check pots when MNS04 was

applied at seeding at 150 to 300 kg ha- or when flooding was imposed (Table 1).

Plants in flooded pots had significantly more leaves than other treatments (Table 1),

and MNS04 applied at seeding at 150 to 300 kg ha-1 provided more leaves than were

found in check pots.

Similar responses to MNS04 drilled with 'Lebonnet' seeds were obtained in two

field studies conducted at the Everglades Research and Education Center on a soil

with pH 7.4. In one study planted April 16, 1986, following a relatively dry period,

seedlings in unflooded check plots died, whereas those recei-v~: MNS04 at seeding at

rates ranging from 50 to 150 kg ha-1 grew well.

A second field study was planted May 28, 1986. There was considerable

rainfall following planting of this study, and the water table was ar.zltSin,: at less

than 60 cm (24 inches). Seedlings in check plots were somewhat chlorotic but grew

fairly well. However greater dry weight production 6-weeks after seeding was

obtained when MNS04 was drilled with the seeds at rates r-'i.n::T from 20 to 60 kg

ha- Growth was not improved over the check plots when ZnSO4 was drilled

with the seed at 20 kg ha or by drilling sulfur (50 to 150 kg ha ~) or

tartaric acid (10 to 100 kg ha-1) with the seed (data not presented).

In a greenhouse trial, 5-week old Skybonnet seedlings grc .,ih) in the

Okeelanta mill pond soil described above were sprayed with Mn (from MNS04) at 5, 10,

or 20 kg ha- Three weeks later the seedlings were harvested. Plant top weight,

root weight, total weight, plant height, and number of leaves per plant all increased

linearly with the rate of Mn spray (Table 2). Nevertheless, MNS04 drilled with the

seed probably would have provided more plant growth 8-weeks after planting than was

obtained in 8 weeks by Mn sprays at 5-weeks.

A

,--i

I

L^^

250

1 i

!l

FO

AB

--- ''------'

ROTo

ROOT

B

J'

TIME RFTER F.ERGENCE (WEEKS)

Fig. 1. Rice seedling weight 6-weeks after emergence in response to an
Fe spray 1, 2, or 3 weeks after emergence, or to FeS04*7H20
drilled at seeding (0), and in check pots (*). Values with
the same letter are not significantly (P<0.05) different by
Duncan's multiple range test.

C

--~--- -I ~-

Bli~

m

"'

c

Table 1. Total weight of 4-week old 'Skybonnet' rice seedlings as affected
by Mn and flooding.

Seedling Plant Leaf
Treatment weight height number

mg/plant

cm

no.

MnSO.H 20 at seeding
300 kg ha 100.5 a 28.8 a 4.3 b

150 82.3 ab 26.7 ab 4.2 b

30 35.5 c 22.4 bc 3.5 cd

3 17.3 c 17.8 c 3.1 d

Flooding 12 days after planting 75.4 b 27.7 a 5.0 a

Seed soaked in Mn solution 26.5 c 18.5 c 3.5 cd

Check 18.0 c 18.8 c 3.0 d

Values within a column followed by the same letter are not significantly
(P<0.05) different by the Duncan's multiple range test.

------ -----.-------------------------------
Table 2. Effect of Mn spray on 'Skybonnet' rice seedling growth.
-----------------------------------------------------------
Mn top Root T-tal Plant Leaf
rate weight weight weight height number
--------------------------- -------------------
-I
kg ha - /plant - -cm no.

0 35.4 6.5 41.8 16.5 4.8

5 55.7 19.4 75.1 19.3 5.0

10 63.2 23.5 86.6 18.1 5.2

20 83.8 37.1 120.8 22.5 5.6

Linear effect ** ** *

** and represent statistical significance at P<0.01 and 0.05,
respectively.

The Use of Calcium Silicate Slag in a Rice--Sugarcane Rotation

on Everglades Histosols

D.L. Anderson, D.B. Jones and G.H. Snyder*

Silicon is a functional plant nutrient that under certain conditions increases

plant gro.th. The importance of Si for plant growth and production was discussed by

Elawad and Green (1979), Lewin and Reimann (1969), and Mengel and Kirkby (1982). In

South Africa, sugarcane ( Saccharum spp.) has responded to soluble silicate

application (Du Preez, 1970). In Hawaii, silicate slags have been used successfully

on various agronomic crops (Plucknett, 1972).

Sugarcane and rice ( Oryza sativa L.) yields have been increased by

application of calcium silicate slag to Histosols in the Everglades Agricultural Area

(EA\). Leaf Si of '- ;rc. grown in the EAA was found to be below or near levels

that limited :,,r;-.c production in Hawaii (Bair, 1966; Gascho, 1976; Gascho, 1977). It

was found that leaf '! c-. -, a :-*Loi associated with low Si levels, could be

reduced and sugarcane and sugar yields could be increased by application of silicate

szF, on organic and mineral soils in the EAA (Gascho and Andreis, 1974; Kidder and

Gascbo, 1977). Further studies showed that application of silicate materials

increased plant height, stem diameter, tillering, and cane and sugar yields in both

the plant and ratoon crops (Elawad et al., 1982). Rice yields were increased on

organic soils of the EA in excess of 30% following pre-plant application of silicate

slag, and positive linear relationships between straw Si content and grain yields

were observed (Snyder, et al. 1986b). In these studies, rice receiving Si slag

*Assistant Professor-Soil/Nutritionist, Assistant !' fr :~r~r-Rice Agronomist,
and Professor-Soil Science, r;,-rect'vely, Everglades REC

-2
application had greater height, greater number of panicles m higher 1000 grain

weight, and less disease. Nevertheless, calcium silicate slag is sufficiently

expensive that its commercial use for rice production alone is uneconomical (J.

Alvarez, Economist, Univ. Fla. personal comm.).

Rice and sugarcane are grown in rotation in the EAA on approximately 4,000 ha.

From this rotation, both economic and agronomic benefits have been observed (Alvarez

and Snyder, 1984; Snyder et al., 1986a). If slag applied to rice also benefits the

sugarcane crop that follows rice, then the economics associated with slag use for

rice are more favorable. The objective of this study was to determine the residual

effect of silicate slag applied to rice on the sugarcane crop following rice.

METHODS AND MATERIALS

Rice

Two studies were conducted at locations approximately 5 km apart in the eastern

EAA, located on Seminole Sugar Corp. The soil in both studies was a Terra Ceia muck

(Euic hyperthermic Typic Medisaprist), a Histosol that accounts for about 40% of the

Everglades under cultivation (McCollum et al., 1978). A calcium silicate slag (Table

1), a by-product of electric furnace production of elemental P, was broadcast in

-1
commercial rice fields at rates of 0, 2.5, 5, 10 and 20 Mg ha- Slag was

incorporated into the soil by tilling to an approximate depth of 15 cm on 12 Apr 1984

in study 1 and on 1 May 1984 in study 2, prior to rice seeding. 'Lebonnet' rice was

seeded on 17 Apr 1984 and 2 May 1984 for studies I and 2, respectively. Plot size

was 6.1 x 10.0 m, and the experimental design was a randomized complete block with 4

replications. Four slag treatments were added at 2.5, 5, 10, and 20 Mg ha-

after rice production ("before cane") on 14 Nov 1984 and 16 Dec 1984 in studies 1 and

2, respectively. The rice was commercially seeded at 100 kg ha-1 in rows spaced

at 18 cm. Iron sulfate ("Iron-Sul", heptahydrate, 1.2% K, 30% S, 20% Fe) was drilled

with the seed at approximately 100 kg source material ha-1 in both studies. As

per commercial practice for rice grown on organic soils in the EAA, no other

fertilizer was used.

The fields were flooded approximately 4 weeks after seedling emergence until

about 2 weeks before the plant crop harvest. Following harvest, the fields were

reflooded for ratoon rice crop production. The fields were maintained using standard

cultural techniques (Shuler et al., 1981). On 7 Aug 1984, the rice grain in study 1

was hand harvested by combining 4 rows, 10 m long in the center of each plot. Straw

was also collected. On 22 Aug 1984 rice grain in study 2 was harvested by hand from

2 rows, 4 m long in the center of each plot. The grain was threshed and the straw

was retained. The same hand harvesting technique was used for the ratoon crop in

study 1 on 24 Oct 1984.

Harvested grain was weighed and moisture was determined'with a commercial grain

moisture meter. Yields were calculated as unhulled rice (rough-rice) at 12%

moisture. Straw Si was determined by dry asking 1.00 g portions at 550 C, following

pre-treatment with HNO3. After washing with HC1, the residue was re-ignited at

550 C and and the final residue weighed as SiO2. Data are reported as Si in

units of dag kg- (%).

Sugarcane

After harvesting the ratoon rice, slag was broadcast on the "before cane" plots.

All plots were prepared for cane planting by rototilling and furrowing so that each

plot contained 4 rows on 1.5 m spacings by 10 m long. In both studies, 40, 100, 5.6,

2.2, 2.2, 1.1 kg ha- of P, K, Mn, Zn, Cu and B, respectively, were placed in the

bottom of the furrow. Double rows of cane stalks, cut to 46-cm lengths, were placed

in the furrow and covered on 17 Dec 1984 and 19 Dec 1984 in studies 1 and 2,

respectively. All cultural practices were the same as those maintained in commercial

fields (IFAS, 1983). Twenty top visible dewlap (TVD) leaf blades, with mid-ribs

(Thein and Gascho, 1980), were collected from each plot in studies 1 and 2, on 3 June

and 20 June 1985, respectively. Analysis for Si in sugarcane leaf samples was

determined as described previously for rice tissues.

Sugarcane harvesting in studies 1 and 2 occurred on 31 Jan and 17 Feb 1986,

respectively. The cane was burned to remove excess leaves and trash, and whole

stalks were cut by hand at the soil surface. The tops were removed by cutting at the

top hard internode. After the cane stalks from each plot were weighed, 15 stalks per

plot were randomly collected and were passed through a 3-roller sample mill for juice

extraction. The crusher juice was analyzed for Brix (soluble solids) using a Bausch

& Lomb refractometer. After clarifying the juice using lead subacetate (Meade and

Chen, 1977, p. 541), pol was determined using a Rudolph Autopol IIS, Automatic

Saccharimeter. The percent sucrose in the juice was estimated using formulas

developed from sucrose tables given by Meade and Chen (1977,.p. 882-885) and

temperature Brix correction tables by Meade and Chen (1977, p. 861-962). Juice

purity was calculated as a percent of the ratio of sucrose to Brix. Recoverable

960 sugar Mg cane-I was calculated using the Winter-Carp-Geerlig's formula

modified by Arceneaux (1935), and the varietal correction factor (VCF) for cv.

CP72-1210 given by Glaz, et. al. (1985) and described by Rice and Hebert (1972).

From the measured cane tonnage (kg ha- ) and theoretically recoverable 960

sugar (kg sugar Mg cane- ), the sugar yield was calculated (kg 960 sugar

ha-). Analyses of variance (ANOVA) and regression analyses of yield components

across time and rate of slag application were performed using SAS (Freund and Linell,

1981; SAS, 1982).

RESULTS AND DISCUSSION

Rice

Calcium silicate increased Si in rice straw from the plant crop in both studies
-1
(Fig. 1). In the absence of applied slag, straw averaged 2.0 dag Si kg In a

previous study (Snyder et al., 1986b) plant crop grain yields were reduced when strav

Si contained less than 3.0 dag Si kg- Straw Si in the ratoon crop in study 1

also increased with applied slag (Fig. 1). No ratoon crop was harvested from study

2, for reasons explained below.

Slag application significantly (P<0.01) increased rough-rice yield in the plant

crop and ratoon crop of study 1 (Fig. 2). Slag applied at 20 Mg ha-1 increased

plant crop rice grain yield by 44%. The highest rate of slag application increased

the ratoon crop yield by 67%.

A very uneven stand of rice was obtained in study 2 because the experiment

inadvertently was planted in a surface depression in the commercial field. At the

time the field was first flooded, the rice in the experimental area was covered with

water sufficiently deep that many seedlings were killed. The excessive in-field

variation in this study was indicated by comparison of the coefficients of variation

for studies 1 and 2; 8.8 and 22.2 respectively. Probably for this reason, there was

no significant difference in rough-rice yield among treatments in study 2. However

the means for the different slag rates were similar to those obtained in study 1,

with the exception of the 20 Mg ha-1 rate. Rough-rice yields corresponding to

slag rates of 0, 2.5, 5, 10 and 20 Mg slag ha-1 were 5.4, 5.5, 6.6, 7.0 and 6.6
-I
Mg ha1, respectively. Based on this trend, and the straw Si data, it appears

that soil Si in study 2 was sufficiently low to limit rice yields. Because of the

uneven plant crop stand, the ratoon crop was not harvested.

Calcium silicate increased the Si in sugarcane leaves, although greater response

occurred with slag applied immediately before sugarcane planting (Fig. 3. In the

absence of Si slag, su.rc,., v..r--.-:ed 1.2 and 1.6 dag leaf Si kg-1 in studies 1

and 2, respectively.

The ANOVA of the data indicated that cane and sugar yields were significantly

affected by the rate and time of slag application, with no significant rate x time

interaction (Table 2). Crusher juice sucrose, Brix, juice purity, stalk weight, and
-1
sugar Mg cane- were unaffected by slag application.

Slag applied for rice production also improved production of the following

sugarcane crop. Nevertheless, slag had a greater beneficial effect on sugarcane

production when applied just prior to sugarcane planting (Fig. 3-5). As a result of

slag application, Mg of cane harvested ha-1 increased from 10 to 23%, and Mg

sugar ha-1 increased from 10 to 25% (Fig. 4 and 5).

CONCLUSION

In Hawaii, 55 to 72% of the applied Si was not utilized by the crop even after 5

years (Khalid and Silva, 1978). In the present studies, sugarcane continued to

benefit from a single application of silicate slag applied before two rice crops,

even though sugarcane yield responses were lower than yields in which slag was

applied immediately prior to planting, sugarcane. For example, when averaged across

both studies, slag applied at 20 Mg ha-1 before rice increased Mg sugar ha-1

16%, compared to a 21% increase when slag was ap-lic. before cane. Since application

and material costs may prohibit use of slag before each crop, the economic benefits

from a one-time application for a long-term rice-sugarcane crop rotation system

appear better and are therefore currently being investigated.

ACKNOWLEDGEMENTS

We would like to extend our appreciation to C. Miller, C. L. Elliott, L. P.

Schwandes, E. A. Figueiras, F. Hernandez, N. Relph, and N. L. Harrison for their

technical support. Mention of a trade name or commercial product does not constitute

endorsement for use by the University of Florida.

REFERENCES

Alvarez, J., and G. H. Snyder. 1984. Effect of prior rice culture

on sugarcane yields in Florida. Field Crops Res. 9:315-321.

Arceneaux, G. 1935. A simplified method of making theoretical

e.ug.r yield calculations. In accordance with Winter-Carp-Geerligs

formula. Int. Sugar J. 37:264-265.

Bair, R. A. 1966. Leaf silicon in sugarcane, field corn and St.

Augustlnerz.',a grown on some Florida soils. Proc. Soil Crop Sci.

Soc. Fla. 26:64-70.

Du Prce, P. 1970. The effect of silica on cane growth. Proc.

S. .'.r. Sorr Technol. Assn. 44:183-188.

Elawad, S. H., G. J. Gascho, and J.-J. Street. 1982. Response

of rr.:;xarc;ne to silicate source and rate. I. Growth and yield.

n ,,. J. 74:481-484.

Elawad, S. H., and V. E. Green. 1979. Silicon and the rice

l-: environment: a review of recent research. II Riso (Milano)

28(3): i-2 -253.

fr-und, R.J., and R.C. Littell. 1 S'.' SAS for linear models. SAS

Institute Inc. Cary, N.C. p. ?.1-184.

C:.c,, G. J. 1976. Silicon status of Florida sugarcane. Proc.

Soil c;,, Sci. Soc. Fla. 36: i10-191.

;,.;>, G. J. 1977. 'e-ponfn of sugarcane to calcium silicate

slag. I. Mechanisms of response in Florida. Proc. Soil Crop Sci.

Soc. :.n. 37:55-58.

Gascho, G.J., and H.J. Andreis. 1974. Sugarcane response to

calcium silicate f~r~r .:ppli to organic and sand soils. Int.

Soc. Su.-.r Cane Technol. 15:543-551.

Glaz, B., P.Y. P. Tai, J.L. Dean, M.S. Kang, J.D. Miller, and 0.

Sosa, Jr. 1985. Evaluation of new Canal Point ;cnarcain". clones,

1984-85 harvest season. USDA/ARS. 24 p.

Khalid, R. A., and J. A. Silva. 1978. Residual effects of calcium

silicate in tropical soils: II. Biological extraction of residual

soil silicon. Soil Sci. Soc. Am. J. 42:94-97.

Kidder, G., and G. J. Gascho. 1977. Silicate slag recommended for

specified conditions in Florida sugarcane. i.r'n, om Facts No. 65.

Fla. Coop. Exten. Ser., Univ. Fla., Gainesville.

IFAS. 1983. Florida agriculture in the 80's. S"i;u.-^ committee

report. pp. 101-116.

Lewin, J., and B. E. F. Reimann. 1969. Silicon and plantgrowth.

Ann. Rev. Plant Physiol. 20:289-304.

McCollum, S.H., O.E. Cruz, L.T. Stem, W.H. Wittstruck, R.D. -1,

and F.C. Watts. 1978. Soil survey of Palm Beach County area,

Florida. -n.-SCS, West Palm Beach, FL, and :riv. FL (IFAS) Soil

Sci. Dept., Gainesville, FL pp. 96.

Mp.I', G. P., and J. C. P. Chen. 1977. Cane sugar handbook. 10th

Ed. John Wiley & Sons, N.Y. pp. 947.

T -ril, K., and E.A. Kirkby. 1982. Principles of plant nutrition.

3rd ed. Intl. Potash Inst. Worblaufen-Bern, Switzerland.

pp. 548-552.

Plucknett, D. L. 1972. The use of soluble silicates in Hawaiian

agriculture. Vol I, No. 6:203-223. Univ. of Queensland :re,

St. Lucia.

Rice, E. R., and L. P. lebert. 1972. Fuyt,:ca.:- vari'-. tests in

Florida during the 1971-72 season. USDA, ;:.,--2, 14 p.

SAS. 1982. Statistical analysis system. SAS Inst. Inc., Cary, N.C.

Shuler, K. D., G. H. Snyder, J. A. Dusky, and W. G. Genung. 1981.

Suggested guidelines for rice production in the Everglades area of

Florida. Everglades Research and Education Center, Belle Glade, FL.

pp. 9.

Snyder, G. H., R. H. Caruthers, J. Alvarez, and D. B. Jones. 1986a.

Sugarcane production in.the Everglades following rice. Proc. Am.

Soc. Sugar Cane Technol. 5:(in press).

Snyder, G. H., D. B. Jones, and G. J. Gascho. 1986b. Silicon

fertilization of rice on Everglades Histosols. Soil Sci. Soc. Am.

J. 50:(in press).

Thein, S., and G. J. Gascho. 1980. Comparison of six tissues for

diagnosis of sugarcane mineral nutrient status. Proc. 16th Congr.

Int. Soc. Sugar Cane Technol. pp. 152-163.

Fig. 1. Effect of Si slag application on rik. ';trAw Si content.

a /s.-"
4.8

4. 2[, 'CAT'". 2

d I r c-P!a-nt Rico
2. 4
2t. --- Rstoesn RIc

0 5 i 15 2
My Slas Ha

Fig. 2. Effect of Si slag application on I. yields in plant
and ratoon rice crops in study 1.

Plant RM~e

.o. .

0 5 i0 Is 20
M-1
Mg *.'- H n

Fig. 3. Effect of time and Si slag application on sugarcane leaf Si content.

3.5- .. 0
T Before Cne .

3.
S5. o

-2.5-

0 2.- Bofore Rice

1.5
C LOCATION 1

B efore Cano .--. ".

3.5
**

Before Rice
J 2. /

LOCATION 2

s 10 / 20I
-1
Mg Slag Ha

59

Fig. 4. Effect of time and Si sl a application o'n Mg of sugaircane harvested ha -1

LOCATION

He-

1 s
Eg Stag

I_..

-

Fig. 5. Effect of time and Si slag application on Mg sugar yield per ha-1.

sv:r Before Cane ..--- --o

r Re
-- 0------

LOCATION 1

0I .0-0
------------------ -----------------------------------

Before Cano .

1A -
o a.
S..- Before Rice

LOCATION 2

B 5 ru S 20
Mg Slag He

Table 1. Chemical analyses of TVA silica slag used in tests.

Element dag kg-

Ca 29.12
Si 20.60
Al 5.18
S 0.37
Fe 0.99
P 0.52
K 0.42
Na 0.15
Mg 0.20

CaCO, Equivalence 46.80
Loss on Ignition 1.34

Analyses done by Alabama Testing
Laboratories, Birmingham, AL 35202

Table 2. Analyses of Variance of sugarcane yield components
significantly affected by the application of Si slag.

Yield
Study Component Source DF Significance R
--------~~'~----~--"------ -- -- -- -- -- -- -- -- -
-1
1 Mg cane ha1 Model 10 ** 0.74
Time I *
Rate 3 **
Time x Slag 3 ns
-1
Mg sugar ha-1 Model 10 ** 0.68
Time 1 *
Rate 3 *
Time x Slag 3 ns

2 Mg cane ha-I Model 10 ** 0.73
Time 1 *
Rate 3 **
Time x Slag 3 ns
-1
Mg sugar ha- Model 10 ** 0.70
Time 1 +
Rate 3 **
Time x Slag 3 ns

** *, +, and ns represents statistical significance at P < 0.01,
0.05, 0.10 and P> 0.10, respectively.

Effect of Flooding on Biochemical Properties of Organic Soils

Used for Rice Cultivation

K. R. Reddy and G. H. Snyder*

Flooding drastically alters the physical, chemical and biological properties of

organic soils, thus influencing the availability of plant nutrients. To assess the

effect of flooding, a series of batch incubation experiments were conducted on

organic soils collected from 9 locations in Everglades Agricultural Area. Parameters

evaluated were: pH, redox potential (Eh), nitrogen, phosphorus, iron and manganese,

organic acids, and sulfides. At present, experiments related to Eh and nitrogen are

complete and the results will be presented.

Redox potential represents the intensity of anaerobiosis in organic soils.

Prior to flooding Eh values were greater than 300 my and after flooding Eh values

decreased steadily and remained constant at -300 to -150 mv in about 4 to 5 weeks

(Fig. 1). During the first week, Eh of the soil decreased slowly, indicating the

buffering capacity of nitrate to maintain Eh at 200 my. Although the soils showed

some variation in Eh values, general trends were same. Under field conditions, Eh

values will be higher than those observed in the laboratory experiments, because of

percolation of water through the soil profile.

Flooding rapidly decreased nitrate content of the soils (Fig. 2). Upon flooding

soil oxygen is consumed by aerobic bacteria, and after oxygen concentration in the

soil reaches to zero level, nitrate is used by bacteria as oxygen source during their

respiration. This process is called denitrification. During this process nitrate is

*Professor-Soil Biochemistry, Central Florida REC, Sanford, FL and Professor-Soil
Science, Everglades REC, Belle Glade, FL, respectively

converted to nitrogen gas. Nitrate content of the soil decreased by about 70-90% in

10 days after flooding. High initial concentration of nitrate may be undesirable to

rice seedlings, since nitrate tends to maintain iron in unavailable form, thus

inducing iron deficiency in rice.

Significant concentrations of nitrite were found in all soils upon flooding

(Fig. 3). Nitrite is an intermediate product during the denitrification process

(Nitrate nitrite nitrous oxide nitrogen gas). Nitrite is very unstable in

flooded soils and is rapidly used by bacteria during their respiration. The effect

of nitrite on rice seedlings is unknown at this time. However, low concentration of

nitrite can be potentially toxic to rice seedlings.

During the first 10 days of flooding, significant concentration of ammonium

accumulated in the soil. Ammonium is the end product during anaerobic decomposition

of soil organic matter. Accumulation of ammonium in the soil profile is beneficial

to rice seedlings since rice plants prefer ammonium over nitrate.

Growing rice on organic soils poses special problems with respect to nitrogen

dynamics. Initial nitrate can be decreased by preflooding the soil prior to the

planting of rice. If possible, seeding of rice under wet soil conditions

(preflooding at least 10 days) is desirable, because this practice reduces nitrate

concentration and increases ammonium and iron concentration, thus decreasing the

problem of iron chlorosis.

moo 41
.00

100

S-1o00

.5 4OANO
-oo00 -

-moo ---

t 2 o -svAN

400

200

200

1 00
aoo

0

-1 00

-200

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400

2O0

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aoQ ''I

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-200 (O,

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0 oZLAIa~4-r. -a te1K0t

.400

1 00 -

-MOO ---m----
-ao o -^
0 ao a d e 20 0

t3 t3M

Fig. 1. Effect of flooding on redox potential of organic soils

46

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240 -

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to o: "roLF H.O-- _^ ^N-

2.Ma0 --
n mo -

100 -
00
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0 RO ----- I--- -----------
1 40

e8
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a

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a-

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a-

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is -
arf
Sa a*- fN 4
t oAW r Hc^- sOURS ^

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a -

Fig 3. Effect of flooding on nitrite nitrogen in organic soils
748
11MI --U-PS-S_

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10 --S F

a 8-

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ma

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049

49

Physiological Traits Associated with Grain Yield of Rice

Grown on South Florida Histosol

F. B. Laroche, D. B. Jones, and F. P. Gardner*

Plant growth and development are essential processes for the propagation of a

species, and they can be expressed as a function of genotype and the environment

(Gardner et. al. 1985). In this study we are concerned with the influence of the

environment on the growth and development of two rice cultivars. Very little is

known about the physiological factors affecting the yield of rice in relation to the

south Florida environment. Therefore, this study was developed to establish

guidelines on the growth and development of rice under south Florida's climate. Our

objective is to understand how the environment affects the growth of rice in relation

to yield. Two cultivars were chosen: 'Lebonnet' which is a tall traditional variety

with droopy leaves, and 'Gulfmont' a short stiff strawed variety with erect leaves.

We want to determine how the two cultivars, which vary considerably in plant type,

perform under south Florida's climate and environment. With information gathered

from this study we can then relate physiological traits such as dry matter

accumulation, partitioning, leaf area index and plant height to yield.

MATERIALS AND *: 'l~.'i S

The two rice cultivars in this study are very similar in growth duration, but

very different in other agronomic traits such as height, leaf angle, and stature.

*Graduate student and Assistant Professor-Rice Agronomist, Everglades
REC and Professor-Plant Physiology, University of Florida, Gainesville,
respectively.

'Lebonnet' is a commercially grown variety, while Gulfmont has just been released in

1985. The experiment was conducted in the summer of 1985 at the Everglades Research

and Education Center in two separate plantings, April 25 and May 16.

Plots (12.0 m x 1.5 m) were drill seeded in a randomized complete block design.

Sampling began four weeks after planting and was repeated every two weeks until

panicle initiation occurred, after which samples were taken weekly. Sampling

consisted of cutting at ground level all of the plants from 4 rows 0.5 m in length.

Samples were brought to the laboratory and weighed. Subsamples of 20 plants were

then taken from each sample, and the plants were separated into leaves, stem (plus

leaf sheath) and panicles. Leaf area, and fresh weight of leaves, stems and panicles

were recorded, and all samples and subsamples were then dried. After drying, dry

weights of all samples were recorded. Height measurements were taken at each time of

sampling. Chemical analysis will be made to determine the amount of carbohydrate and

nitrogen present in different plant parts at different stages of plant development.

RESULTS AND DISCUSSION

Plant Height

Both cultivars grew at a fairly continuous rate in the April planting,

increasing in height almost up to maturity, Figure 1. In the May planting, plant

height of both cultivars increased rapidly for the first 12 weeks at which time

maximum plant height was obtained. Maximum plant height was greater for both

cultivars in the May planting, being 3 and 11% more for 'Gulfmont' and 'Lebonnet,'

respectively. This response indicates 'Lebonnet' partitioned proportionally greater

growth to plant height in the May planting than did 'Gulfmont'.

Leaf Area Index (LAI)

Leaf area index (LAI) is the ratio of total plant leaf area per unit ground

area. LAI is related to the amount of sunlight the plant intercepts and thus can use

for plant growth. In the absence of lodging, LAI is frequently related to grain

yield. LAI values necessary to intercept 95% of the incident sunlight in a rice

canopy suggest that a LAI of 4-8 is needed for good growth (Yoshida, 1981). In both

plantings, both cultivars reached maximum LAI 10 weeks after planting, after which

LAI began to steadily decline. In the May planting, LAI increased more rapidly and

reached a maximum of almost twice of that of the April planting for both cultivars.

Although LAI decreased more rapidly in the May planting it still remained higher at

maturity than the April planting. 'Lebonnet' had a higher LAI in the April planting

than 'Gulfmont', while 'Gulfmont' was highest in the May planting. Differences

between cultivars were relatively small though when compared to differences in LAI

between planting dates.

Development of Plant Parts Dry Weight

Dry weight consists of the inorganic compounds absorbed by plant roots, but the

amount accounts for only 10 20 per cent of the total. A great part of the dry

weight consists of the carbohydrates produced in the process of photosynthesis. Dry

waiLht is a major factor in determining the final product of growth and development,

grain production. The dry weight of leaves, stems, panicles and total plant is

illustrated in Figure 3.

The total dry weight is obtained from the sum of leaf dry weight, stem dry

weight and panicle dry weight (when present). The curve for total dry weight is an S

shaped (Sigmoid) growth curve. In this type of curve, three growth phases can be

detected: the logarithmic phase, the linear phase and the senescence phase

(Salisbury and Ross, 1985). During the logarithmic phase, which occurs from week one

to week four, the size of the plant increases exponentially with time. The growth

rate is slow at first but increases at an increasing rate. In this phase the rate of

growth is proportional to the size of the plant at any given time, meaning conditions

for healthy early seedling growth will increase the growth rate of the rice plant.

In the everglades area, this phase of growth can be affected by factors such as

micronutrient deficiencies or herbicide damage. Phase 2, which starts at the fifth

week and goes through week thirteen, is the linear growth phase. At this stage,

increase in size continues at a constant, usually maximum, rate of growth. In this

phase, the panicle primordia developed, the stem elongates, and panicle

differentiation and spikelet development takes place. An ample supply of nitrogen

can cause an increase in the number of spikelets per panicle during this period. The

linear rate is followed by a period of declining rate in phase three, the senescence

phase. The increases in growth become progressively less until a steady state is

reached. This steady state phase is referred to as maturity.

The panicle dry weight curve is similar in shape to the total dry weight curve.

It represents growth of the panicle during the fruiting stage from heading to

maturity, which occurred from week eleven through week sixteen. Grain growth of

rice, or any field crop, is initially slow, enters a linear phase, and then slows

down toward maturity. The linear phase is the grain filling period, during which

most of the dry weight of the grain is obtained. The stem dry weight curve on the

other hand, has somewhat of a different shape than the previous two curves discussed.

The stem dry weight increases gradually until week ten when panicle initiation

occurs, and then decreases sharply there after and levels off during the final 3

weeks. This decrease in stem weight indicates the plant is redistributing

carbohydrates. Stems in some instances serve as temporary storage organs. After

panicle initiation, dry matter that was produced by the plant during the vegetative

phase and stored in the stems, can be translocated from the stems to panicles. As

much as 21% of the grain carbohydrates has been reported as coming from previously

stored carbohydrates during the grain filling period (Cock and Yoshida, 1972; Van Dat

and Peterson, 1983). The dry weight curves of leaves increases as growth advances

and reaches a maximum at or around panicle initiation. The growth rate of leaves is

constant thereafter, and decline slightly toward maturity. The decline is due to the

death of lower leaves.

In comparing the two cultivars, their total dry weight was similar at each

planting date. Panicle dry weight was also similar for both cultivars in the April

planting, however, in the May planting, Gulfmont had a higher panicle dry weight.

From the stem dry weight growth curve, it appears 'Gulfmont' translocated more

carbohydrates from the stem to the panicle, thus indicating 'Gulfmont' was more

efficient in partitioning carbohydrates to yield in this planting. There were no

differences in leaf dry weight between cultivars in either planting. The 100 grain

weight was similar for both varieties at each planting. However, 'Gulfmont'

outyielded 'Lebonnet' at both planting dates, due mainly to the higher number of

panicles (Table 1).

Under certain conditions such as deep water, a taller cultivar (110-130 cm) may

be considered more desirable over a short stature (80-100 cm). However, grain yield

decreases with increasing water depth even when a tall cultivar is utilized (Yoshida,

1981). A taller plant however, is more susceptible to lodging and less responsive to

nitrogen, and is therefore limited in yield potential. Also, even though LAI's were

nearly similar for both cultivars, the size of LAI needed to give maximum crop

photosynthesis depends on leaf orientation of the canopy. Erect leaves allow the

sunlight to penetrate deeper into the canopy. Consequently the erect leaved canopy

achieves greater photosynthesis which result in better yield. In a canopy of tall

plants were there is mutual shading of leaves, less light is able to penetrate the

canopy, which results in less photosynthesis, and lower yield. This appears to be

the case in this study. With the exception of situations where adequate water depth

control can not be achieved, semi-dwarf cultivars appear to be well adapted to the

EAA. They posses the necessary traits to produce high yields under intensive

management, yet give yields equal to or better than taller cultivars under less

favorable yield conditions, such as low N fertility and/or late planting.

References Cited

Yoshida, S. 1981. Fundamentals of rice crop science. International Rice

Research Institute. p. 195-230.

Salisbury, F. B. and C. W. Ross. 1985. Plant physiology. Third Edition.

Wadsworth Publishing Company, Belmont, California. p. 290-300

Gardner, F. P., R. B. Pearce and R. L. Mitchell. 1985. Physiology of crop

plants. First Edition. Iowa State University Press. Ames. p. 187-207.

Van Dat, T. and M. L. Peterson. 1983. Performance of near isogenic

genotypes of rice differing in growth duration II. Carbohydrate partitioning

during grain filling. Crop Science 23:243-246.

Cock, J. H., and S. Yoshida. 1972. Accumulation of "C-Labeled carbohydrate

before flowering and its subsequent redistribution and respiration in the rice

plant. Proc. Crop Science Society of Japan. 41(2):226-234.

Table 1 Days to heading, yield components and yield of two rice
cultivars grown at two planting dates.

Early Planting Late Planting

100 100
Cultivar Heading Grain Panicle Yield Heading Grain Panicle Yield
Weight No. Weight No.

-2 -1 -2 -1
Days from gm m kg ha Days from gm m kg ha
planting planting

Lebonnet 82 2.51 286 4096 81 2.41 305 3580

Gulfmont 82 2.51 305 4298 81 2.44 425 4685

Figure 1 Height curves of two varieties at two planting dates.

EARLT PLANTING

8 1W 1
WEEKS

LRTE PLANTING

0 2 4 6

WEEKS

4 LEBONNET
0 GULFMONT

Figure 2 Leaf Area Index of two cultivars planted at two dates. 1985.

ERRLT PLfNTING

LATE PLANTING

L

6F
S
4
3-
2

2!

-- I I I

S 2 .4 6 8 10

WEEKS

12 14 16 18

0 2

4 6 8 10 12 14 16 11

WEEKS

GULFMONT
LEBONNET

Figure 3 Growth curves of various plant parts of two cultivars planted at
two dates in 1985.

ERRLT PLANTING

LE PIT3'i T

GULFRONT

1800

1200BB
1000
1880

8800

40088

S 2

WEEKS

12 14 16

WEEKS

LTE "LTI G

LEBOIET
1888.
16g0F
1480
121 /
12 ,
oto

S 2 4 6 6 1 12 14 6
WEEKS

GULFMHQT

18B0
IG a
1400
1200L

8000
8B0L
'- ;*L"

* TOTAL DRY I'E).G iT

SPANICLE DRY WEIGHT

* STEM DRY '-.':IiT

* LEAF DRY WEIGHT

Ratoon Crop Management

D. B. Jones*

This is a summary report of several experiments which have been conducted on

ratoon rice over a period of years by various researchers.

A. Main Crop Seeding Rate x Row Spacing Effects on Ratoon Crop Performance -

D. B. Jones and G. H. Snyder.

Two rice cultivars varying in plant type (Tall = 'Lebonnet'; Semi-dwarf =

'Lemont') were seeded at three rates (50, 100, 150 kg ha-1 seed) in three row

spacings (15, 20, 25 cm) over three cropping seasons. The main crop was grown

and harvested using standard cultural practices. After harvest, the main crop

stubble was mowed to a height of approximately 25 cm and reflooded. At maturity

the ratoon crop was hand harvested and the yield and yield components were

recorded. Row spacing had no effect on any of the yield components and thus no

effect on yield. Increasing main crop seeding rate increased ratoon crop panicle

number for both cultivars in all plantings, while decreasing filled grain number

per panicle. Grain weight was not affected by seeding rate. Compensation

between panicle number and grain number per panicle was complete and therefore,

main crop seeding rate had no effect on yield. Thus, main crop seeding rates and

row spacings appear to have no effect on ratoon crop yield, over the ranges of

seeding rates and row spacings investigated in this study.

*Assistant Professor-Rice Agronomist, Everglades REC

B. The Effect of Main Crop Cutting Height on Ratoon Crop Yield D. B. Jones.

Three rice cultivars, Lemont (LMNT), Lebonnet (LBNT) and Skybonnet (SKBT)

were harvested at maturity at five cutting heights (10, 20, 30, 40, 50 cm) above

the soil surface to study the effects of cutting height (stubble height) on

ratoon crop agronomic performance, yield and yield components. The three

cultivars were chosen because of their different agronomic traits. Cutting

Ie!iht had a significant effect on ratoon crop maturity and mature ratoon plant

h,-lgr. Plant crop grain yields were not significantly different among cultivars

while ratoon crop yields were. The ratoon crop/plant crop yield ratio (RC/PC)

for cultivars over all cutting heights ranged from 34-65%. The RC/PC yield ratio

for cutting height over all cultivars ranged from 37-53%. These figures

represented a ratoon crop yield difference of 40 and 100%.attributable to cutting

height and cultivar, respectively. Therefore, it appears that cultivar selection

has more rf :.c on ratoon crop yields than cutting height, although cutting

height does significantly effect yields.

C. The Effect of Water Management on Ratoon Crop Regrowth D. B. Jones and

G. H. Snyder.

Two fields of rice were planted 3 weeks apart in 1985 (Table 1). The fields

were managed similarly except for the time of draining of the main crop. Main

crop l :.d;ir was similar (3 days difference) for both plantings. The first

planting (Field #1) was drained for harvest 113 days after planting (29 days

after heading) while the second planting (Field #2) was drained 97 days after

planting (16 days after heading) and thus compared to Field #1, 16 days earlier.

Both fields were harvested and reflooded similarly with respect to days from

planting. Yet, the ratoon crop of Field #2 headed 14 days earlier than Field #1.

When comparing ratoon crop regrowth and development for the two fields with

respect to water management (main crop drainage and ratoon crop reflooding) Field

#1 ratoon heading occurred 53 days from drainage and 46 days from reflooding

while Field #2 was 55 and 31 days respectively. Therefore, although there was

approximately two weeks difference between the two fields when comparing ratoon

crop development from main crop planting date and ratoon crop reflooding there

was only 2 days difference when comparing them on the basis of days from main

crop drainage. Thus, it appears that the drainage of the main crop is the

stimulus for ratoon crop regrowth to b-.;u and therefore is a critical factor in

ratoon crop management.

D. Nitrogen Fertilization of Ratoon Rice D. B. Jones and G. H. Snyder.

The same two fields as mentioned in Section C. were used for a timing cf

nitrogen application study in ratoon rice. In Field #1, nitrogen was applied to
-1
the ratoon crop at a rate of 60 kg ha- N at 1, 3 and 5 weeks after

reflooding. Two semi-dwarf cultivars, 'Lemont' and 'Gulfmont', were utilized.

Although grain yields were not obtained because of severe bird idamag, flag leaf

area, which gives a relative indication of nitrogen response, was recorded. Both

cultivars had a significant increase in flag leaf area when nitrogen was applied

3 weeks after reflooding of the main crop stubble, Table 2. This application

time was 28 days after main crop draining. Ratoon crop heading for 'Lemont' and

'Gulfmont' occurred 55 and 53 days after main crop draining. Therefore, the

greatest N response as measured by flag leaf area occurred when N was applied at

approximately the panicle initiation stage of development for the ratoon crop, 27

and 25 days before h.-iring for 'Lemont' and 'Gulfmont', respectively.

In Field #2, two N rates, 60 and 120 kg ha-1 were applied to 'Lebonnet'.

The 60 kg ha- N rate was applied at 0, 2 and 4 weeks after reflooding while

the 120 kg ha- N rate was applied only at 2 and 4 weeks after reflooding.

The greatest N response was found when 60 kg ha- was applied at 0 weeks
-1
after reflooding, Table 3. No response was found at the 120 kg ha- rate.

Since Field #2 was drained considerably earlier than Field #1, reflooding

occurred 27 days after main crop draining in Field #2 as compared to 7 days after

main crop draining of Field #1. As mentioned in the previous section, drainage

of the main crop stimulates ratoon crop regrowth. Therefore, in Field #2,

reflooding occurred only 26 days before ratoon heading, or approximately at

-I
ratoon panicle initiation. This not only explains why the 60 kg ha N rate

at 0 days after reflood gave the greatest response but also why there was a lack

of response to the 120 kg ha-1 N rate, since the first application at this

rate was applied only 12 days before ratoon heading, or approximately two weeks

after ratoon panicle initiation.

In summary, the greatest response to N application on ratoon rice, as

measured by flag leaf area in this study, occurs when N is applied at ratoon

panicle initiation, which seems to occur 25-30 days after main crop drainage.

E. Occurrance of Rice Stink Bugs in Ratoon Rice D. B. Jones and R. H. Cherry.

Although growers are quite aware of the occurrence of rice stink bugs in

main crop rice fields, ratoon rice appears to receive much less attention. In a

two year study during which stink bugs were collected weekly throughout both the

main and ratoon crops, stink bugs appeared in rice fields beginning in June and

were found continuously up to ratoon crop harvest, Fig. 1. Ratoon crop heading

of rice occurs 40-50 days after harvest of the main crop but is typically less

synchronous than that of the main crop. Stink bugs were found to increase

steadily in ratoon fields shortly after harvest, probably feeding on late heading

tillers from the plant crop, Fig. 2. Then, from 80 to 110 days from heading of

the main crop, stink bug numbers increased rapidly and steadily. This period

corresponds to the grain filling period of the ratoon crop. During the two years

of this study, no insecticides were applied to any of the ratoon fields, and all

fields exceeded economic threshold levels. Therefore, growers should monitor

stink bug levels in ratoon rice fields and treat when appropriate, or losses in

both yield and quality may occur.

Table 1. Ratoon crop heading in relation to main crop activities.

Main Crop Activity Ratoon Crop Heading*

Field Planting Heading* Drain Harvest Reflood Time from Time from Time front
No. Date MC Planting Reflood 1MC Drair

-------------Days from Planting---------- ----- ----------Days----------

1 April 25 84 113 120 120 166 46 53

2 May 16 81 97 119 121 152 31 55

2 vs 1 22 -3 -16 -1 1 -14 -15 2

Days to heading are based on the mean of 'Lebonnet', 'Lemont' and
'Gulfmont'.

Table 2. Ratoon flag leaf area and time of N application in relation to main
crop drainage and ratoon crop heading of two rice cultivars.

Cultivar Time of N N Rate Flag Leaf Time from Time from
Application Area MC Drain RC Heading

-1 2
weeks after kg ha cm /30 leaves days days
reflood

LEMONT 0 0 583 7 -48
1 60 654 14 -41
3 60 867 28 -27
5 60 608 42 -13

GULFMONT 0 0 583 7 -46
1 60 649 14 -39
3 60 823 28 -25
5 60 557 42 -11

Table 3. Ratoon flag leaf area and time of two N rate applications in
relation to main crop drr.i:'.: and ratoon crop heading.

Cultivar Time of N N Rate Flag Leaf Time from Time from
Application Area MC Drain RC Heading

-1 2
weeks after kg ha cm /30 leaves days days
reflood

L-o; ET 0 0 838 27 -26
0 60 1183 27 -26
2 60 862 41 -12
4 60 876 55 2

0 0 841 27 -26
2 120 828 41 -12
4 120 824 55 2

U3 _. M nAVEST r InV(
a-

SI% 70- _nSLyTrc fields

L 6 SECT

:it

40-

6 -20 0 20 49 A0 6 0

ORTS FROM MAIN-CROP HERDING

Fig. 1. Abundance of 0. p with respect to crop growth stage
(days from 50%-heading of main-crop) in southern Florida
rice fields.

The Collection of Life History Data for the Crawfish

Procambarus Fallax and P. Alleni, in Regard to

Their Aquaculture Potential in South Florida

K. Fucik*

Rice is grown in rotation with sugarcane and vegetables in the Everglades.

The flood culture used for rice helps reduce soil-subsidence. Nutrients in

drainage water may be removed when the water is used to flood rice fields. In

Louisiana crawfish are produced in conjunction with rice, providing additional

income. The question remains as to whether crawfish could be raised profitably

in conjunction with rice in the Evef-ilde-.

Procambarus fallax and P. alleni are crawfish species native to south

Florida and would be acceptable aquaculture species to state regulatory

agoncie.. !Ii-:-'-, little is currently known about the basic life histories of

these species. Similarly, it is not known whether the nitrate and CaCO3

levels in the surface waters of the EAA will limit the aquaculture potential of

these species. A study has been designed to collect these data through field

surveys and '.i :.-atory studies cdutn: Phase I. It is anticipated that the

crawfish will be grown in outdoor ponds in conjunction with aquatic crops during

Phase II. The facilities of the University of Florida's Everglades Research and

Education Center will be utilized during these investigations.

The commercial applications of this project are twofold. First, it is

expected that the successful conduct of this project could lead to development

of an extensive aquaculture industry in south Florida, Continental Shelf

*Environmental Specialist, Continental Shelf Associates, Inc., Jupiter, FL

Associates, Inc. (CSA) would provide the technology needed to develop the

industry. Second, CSA will our;~'.E part' c rPon l inin .--j"-icture operations

through joint ventures with local farmers.

DELLA

NEWBONNET

LEMONT

LEBONNET

SKYBONNET

BOND

LABELLE

TEBONNET

-r

PROPANIL
PHYTOTOXICITY

MANGANESE STUDY

GERMPLASM
REJUVINATION

PROPANIL PHYTOTOXICITY

EVri.':L.-. E REC RSSEARCIH PLOTS

CONTROL OF VOLUNTEER RICE WITH VEGETABLE HERBICIDES

VERY EARLY MATURITY RICE PERFORMANCE TRIAL

WEED SEED INCREASE

EARLY/MIDSEASON MATURITY RICE PERFORMANCE TRIAL

EVALU-'TION OF PROPANIL PHYTOTOXICITY TO RICE
------------------------------------------------------------------

PHYSIO' :'.;[ :, TRAITS ASSOCIATED WITH RICE GRAIN YIELD

EFT:i.'.T OF MAIN CROP -':'-"; L;IZATION ON RATOON CROP YIELD

TIMING OF RATOON CROP N-FERTILIZATION
TIMING OF RATOON CROP N-FERTILIZATION

	Copyright
	Title Page
	Table of Contents
	Using IFAS rice budget generator...
	Distribution of rice stink bugs...
	Weed management systems in everglades...
	Correcting seedling micronutrient...
	The use of calcium silicate slag...
	Effect of flooding on biochemical...
	Physiological traits associated...
	Ratoon crop management (D. B. Jones...
	The collection of life history...